Method and apparatus for subcutaneously advancing a device between locations

ABSTRACT

A method and apparatus ( 10 ) for advancing a device ( 12 ) underneath the skin ( 102 ) in a mammalian body comprises a casing ( 50 ) made of a magnetic material. The casing ( 50 ) has a closed tip ( 64 ) at one end and an aperture ( 65 ) in an opposite end. The casing ( 50 ) includes an annular inner surface ( 70 ) that defines a cavity ( 76 ) within the casing for receiving a device ( 12 ) that projects through the aperture ( 65 ). The casing ( 50 ) further includes structure for attaching to the device ( 12 ). The casing ( 50 ) is operable to advance the device ( 12 ) through tissue ( 100 ) underlying the skin ( 102 ) in response to movement of a magnetic field across the skin.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/353,695, filed on Feb. 1, 2002.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus forsubcutaneously advancing a device between different locations in amammalian body.

BACKGROUND OF THE INVENTION

An increasing number of patients with neurological disorders, such asepilepsy and Parkinson's disease, are undergoing surgery to implantdevices for treating the disorders using techniques such as deep brainstimulation. The implanted devices can include an electrode that isimplanted into the brain and/or a cerebrospinal fluid shunt implantedinto the patient's head. The implanted devices can also include astimulator device that is implanted into the patient's chest. Thestimulator is then connected to the implanted electrode by an electricallead that is run underneath the patient's skin (epidermis and dermis)between the patient's head and the patient's chest. The stimulator canbe activated automatically or manually to electrically stimulate thebrain via the implanted electrode and thereby curb or prevent seizuresor other symptoms caused by neurological disorders. In the case of thecerebrospinal fluid shunt being implanted in the patient's head, it isoften necessary to run a catheter underneath the patient's skin andconnect the catheter to the implanted shunt.

One complication with the aforementioned surgical procedures andtreatment methods is that the process of tunneling through the tissueunder the skin to extend either a electrical lead or a catheter betweenthe patient's head and chest can be quite time consuming and requiresthat the patient be under general anesthesia for a relatively longperiod of time. The tunneling process typically involves the use of along tunneling rod to push/pull the electrical lead, or the catheter asthe case may be, between the patient's head and chest. Such a tunnelingrod can be hard to use and inaccurate at times. Hence, a need exists fora fast, simple, and accurate method and apparatus for subcutaneouslyadvancing an electrical lead or a catheter between a patient's head andchest.

SUMMARY OF THE INVENTION

The present invention is an apparatus for advancing a device underneaththe skin in a mammalian body. The apparatus comprises a casing made of amagnetic material. The casing has a closed tip at one end and anaperture in an opposite end. The casing includes an annular innersurface that defines a cavity within the casing for receiving a devicethat projects through the aperture. The casing further includes meansfor attaching to the device. The casing is operable to advance thedevice through tissue underlying the skin in response to movement of amagnetic field across the skin.

The present invention further includes an apparatus for subcutaneouslyadvancing an elongated member between different locations in a mammalianbody. The apparatus comprises a casing having a shape like a bullet andmade of a magnetic material. The casing has oppositely disposed firstand second ends. The first end is closed and forms a tip portion of thecasing for tunneling through tissue underlying the skin. The second endis open to form a mouth portion of the casing. The casing includesannular inner and outer surfaces that extend between the first andseconds ends and which define a side wall portion of the casing. Theinner surface further defines a cavity within the casing for receiving adistal end portion of the elongated member that projects through themouth portion. The inner surface includes means for releasablyconnecting with the distal end portion of the elongated member. Thecasing is operable to advance the elongated member through the tissueunderlying the skin between different locations in the body in responseto movement of a magnetic field across the skin extending between thelocations.

The present invention also provides a method for advancing a deviceunderneath the skin in a mammalian body. According to the inventivemethod, a casing made of a magnetic material is provided. The casing hasa closed tip at one end and connecting means for attaching to a device.The device is attached to the casing with the connecting means. Thecasing is inserted underneath the skin of a mammalian body in a firstlocation. A magnetic field source is positioned over the casing. Themagnetic field source is moved across the skin from the first locationto a second location which causes the casing, and the device attachedthereto, to correspondingly advance through the tissue underlying theskin to the second location.

The present invention further provides a method for subcutaneouslyadvancing an elongated member between different locations in a mammalianbody. According to this method, a casing having a shape like a bulletand made of a magnetic material is provided. The casing has oppositelydisposed first and second ends. The first end is closed and forms a tipportion and the second end is open to form a mouth portion. The casingfurther includes annular inner and outer surfaces that extend betweenthe first and seconds ends. The inner surface defines a cavity withinthe casing and includes means for releasably connecting with the distalend portion of the elongated member. The elongated member is insertedthrough the aperture in the casing and attached to the elongated member.The casing is inserted underneath the skin of a mammalian body in afirst location. A magnetic field source is positioned over the casing.The magnetic field source is moved across the skin from the firstlocation to a second location which causes the casing, and the elongatedmember attached thereto, to correspondingly advance through the tissueunderlying the skin to the second location.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will becomeapparent to those skilled in the art to which the present inventionrelates upon reading the following description with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic side view illustrating an apparatus forsubcutaneously advancing a device between different locations within amammalian body in accordance with the present invention;

FIG. 2 is a perspective view of the apparatus of FIG. 1 and shows theapparatus in a different condition;

FIG. 3 is a schematic sectional view of the apparatus of FIG. 1 as theapparatus being advanced subcutaneously; and

FIG. 4 is a view similar to FIG. 3 illustrating an alternate embodimentof the present invention.

DESCRIPTION OF EMBODIMENTS

The present invention relates to a method and apparatus forsubcutaneously advancing a device between different locations in amammalian body. In accordance with a first embodiment of the presentinvention, FIG. 1 illustrates an apparatus 10 for subcutaneouslyadvancing an electrical lead 12 between a first location 14 in apatient's head 16 and a second location 18 in the patient's chest 20.The electrical lead 12 is an elongated, insulated wire having oppositelydisposed first and second ends 22 and 24.

As shown in FIG. 1, an electrode 30 for stimulating a patient's brain isimplanted into the brain (not shown) through an incision (osteotomy) atthe first location 14 in the patient's head 16 in a known manner. Afirst connector 32 for connecting with the first end 22 of theelectrical lead 12 is disposed at a proximal end 34 of the electrode 30.

As is known in the art, a stimulator 40 is implanted into the patient'schest 20 through an incision (not shown) at the second location 16. Thestimulator 40 includes means (not shown), such as electrical contacts ora receptacle, for connecting with the second end 24 of the electricallead 12.

The apparatus 10 comprises a casing 50 made of a magnetic material, suchas an appropriate stainless steel. The casing 50 has an outer diameterbetween 3 mm and 10 mm. As shown in FIG. 2, the casing 50 has aclamshell-type configuration formed by first and second body portions 52and 54. The body portions 52 and 54 are connected by a hinge 56 and thusare movable relative to each other. The casing 50 includes a closuremechanism, schematically illustrated by reference numbers 58 a and 58 b,for securing the body portions 52 and 54 together.

Referring now to FIG. 3, the casing 50 has a shape like a bullet andincludes oppositely disposed first and second ends 60 and 62. The firstend 60 is closed and forms a tip portion 64 for tunneling through tissueunderlying the patient's skin. The tip of the tip portion 64 has asemi-blunt shape which allows it to be sharp enough penetrate tissue,such as fascia, but which restricts the tip from poking out through theskin. The second end 62 of the casing 50 includes an aperture 65 thatforms a mouth portion 66.

The casing 50 further includes annular inner and outer surfaces 70 and72 that extend between the first and second ends 60 and 62 of thecasing. The inner and outer surfaces 70 and 72 define a side wallportion 74 of the casing 50. Further, the inner surface 70 of the casing50 defines a cavity 76 for receiving the first end 22 of the electricallead 12. Inside the cavity 76, the casing 50 may also include a weightedflange 78 adjacent the mouth portion 66. The weighted flange 78 helps tokeep the tip portion 64 of the casing 50 pointed straight ahead so thetip portion does not inadvertently poke through the skin.

A plurality of supports 80 extend radially inward into the cavity 76from the inner surface 70 of the casing 50. The supports 80 are spacedcircumferentially apart and each support includes an engagement pad 82for engaging the first end 22 of the electrical lead 12.

The apparatus 10 further comprises a magnet 90 for providing a magneticfield that attracts the casing 50 and causes movement of the casingcorresponding to movement of the magnet. The magnet 90 may be movedeither manually or by a mechanism (not shown).

Following implantation of the stimulator 40 in the patient's chest 20,the second end 24 of the electrical lead 12 is connected to thestimulator. The electrical lead must now be run underneath the skin fromthe second location 18 in the patient's chest 20 to the first location14 in the patient's head 16.

To subcutaneously advance the electrical lead 12 from the secondlocation 18 to the first location 14, the first end 22 of the electricallead is first connected to the casing 50. The first and second bodyportions 52 and 54 of the casing 50 are spread apart and the first end22 is placed into the cavity 76 with the remainder of the lead 12projecting out of the casing 50 through the aperture 65. When the bodyportions 52 and 54 of the casing 50 are brought together and secured toone another by the closure mechanism 58 a and 58 b, the engagement pads82 in the cavity 76 press against the first end 22 of the electricallead 12 with an interference fit that secures the casing to theelectrical lead.

Next, the casing 50, with the electrical lead 12 attached, is insertedunderneath the patient's skin in the second location 18. Morespecifically, the casing 50 is inserted into the fascia layer 100 justbelow the skin 102, which consists of a dermis layer 104 and anepidermis layer 106, as shown schematically in FIG. 3.

The magnet 90 is then positioned directly over the casing 50 outside ofthe skin 102 so that the casing is attracted by the magnetic field ofthe magnet. The magnet 90 is then moved across the skin 102 from thesecond location 18 toward the first location 14. This movement of themagnet 90 causes the casing 50, as well as the electrical lead 12attached thereto, to correspondingly advance through the fascia layer100 toward the first location 14 as shown schematically in FIG. 3.Continued movement of the magnet 90 allows the casing 50 to tunnel itsway between the two locations, taking the electrical lead 12 along withit, as shown schematically by the dashed line in FIG. 1.

When the casing 50 reaches the first location 14 in the patient's head16, the casing is disconnected from the first end 22 of the electricallead 12 by opening the closure mechanism 58 a and 58 b on the casing.The first end 22 of the electrical lead 12 can then be connected to theconnector 32 on the end of the electrode 30 so that the stimulator 40 isoperatively coupled with the electrode and treatment of the neurologicaldisorder can begin.

Using the apparatus 10 as described above reduces the amount of timerequired to tunnel the electrical lead 12 between the first and secondlocations 14 and 18, and thereby reduces the length of time that thepatient is kept under general anesthesia. The method and apparatus 10described above provides a simple and accurate way to complete thetunneling process with lower risk of pneomothorax and inadvertent skinpenetration that the conventional tunneling rod technique. Additionally,the apparatus 10 can lower the chances of infection by tunneling drainsat a farther site from the incision, as it has been shown that longertunnel lengths result in less infections.

FIG. 4 illustrates an apparatus 210 in accordance with an alternateembodiment of the present invention. In FIG. 4, parts of the apparatus210 that are identical to parts of the apparatus 10 described above areidentified by the same reference numbers.

The embodiment shown in FIG. 4 illustrates how the present invention isadaptable for use in advancing a catheter 212, used in connection withan implanted cerebrospinal fluid shunt (not shown), under the patient'sskin 102. The catheter 212 has a first end 222 that includes a connector226.

The apparatus 210 comprises a magnetic casing 250 that is nearlyidentical to the casing 50 previously described, but does not includeany structure projecting into the cavity 76 in the casing for engagingthe catheter 212 or the connector 226. Rather, the casing 250 is securedto the catheter 212 by capturing the connector 226 inside the cavity 76.A portion 274 of the inner surface 70 at the second end 62 of the casing250 engages the connector 226 and keeps the catheter 212 from movingaxially relative to the casing.

The apparatus 210 functions like the apparatus 10 to enable thesubcutaneous advancement of the catheter 212 from the second location 18to the first location 14 through corresponding movement of the magnet90. Consequently, the apparatus 210 enjoys all of the same benefits andadvantages as are described above for the apparatus 10.

It should be understood to those skilled in the art that the presentinvention may be applied to achieve subcutaneous advancement of manytypes of devices and should not be limited to electrical leads andcatheters. Further, it should also be appreciated that the devicesdisclosed herein can be advanced subcutaneously from any startinglocation to any ending location and should not be limited to tunnelingfrom a patient's chest to a patient's head or vice versa.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes and modifications within the skill of the art areintended to be covered by the appended claims.

1. An apparatus for advancing a device underneath the skin in amammalian body, said apparatus comprising: a casing comprising at leasttwo body portions that are movable relative to each other, said casingmade entirely of a magnetic material, said casing having a closed tip atone end and an aperture in an opposite end; said casing including anannular inner surface that defines a cavity within said casing forreceiving a device that projects through said aperture; said casingfurther including means for attaching to the device; said casing beingoperable to advance the device through tissue underlying the skin inresponse to movement of a magnetic field across the skin.
 2. Theapparatus of claim 1 wherein said device comprises an electrical lead.3. The apparatus of claim 1 wherein said device comprises a shuntcatheter.
 4. The apparatus of claim 1 further comprising a magnet forproviding a magnetic field that is movable across the skin to causecorresponding subcutaneous movement of said casing.
 5. The apparatus ofclaim 1 wherein said at least two body portions of said casing areconnected to each other by a hinge.
 6. An apparatus for advancing adevice underneath the skin in a mammalian body, said apparatuscomprising: a casing made entirely of a magnetic material, said casinghaving a closed tip at one end and an aperture in an opposite end; saidcasing including an annular inner surface that defines a cavity withinsaid casing for receiving a device that projects through said aperture;said casing further including means for attaching to the device thatinclude at least one support extending from said inner surface of saidcasing; said casing being operable to advance the device through tissueunderlying the skin in response to movement of a magnetic field acrossthe skin.
 7. The apparatus of claim 6 wherein said at least one supportincludes an engagement pad for pressing against the device with aninterference fit.
 8. The apparatus of claim 1 wherein said means forattaching to the device includes a portion of said inner surface.
 9. Theapparatus of claim 6 wherein said means for attaching to the deviceincludes a plurality of supports extending from said inner surface ofsaid casing.
 10. An apparatus for subcutaneously advancing an elongatedmember between different locations in a mammalian body, said apparatuscomprising: a casing comprising at least two body portions that aremovable relative to each other, said casing made entirely of a magneticmaterial, said casing having oppositely disposed first and second ends,said first end being closed and forming a tip portion of said casing fortunneling through tissue underlying the skin, said second end being opento form a mouth portion of said casing; said casing including annularinner and outer surfaces that extend between said first and second endsand which define a side wall portion of said casing, said inner surfacefurther defining a cavity within said casing for receiving a distal endportion of the elongated member that projects through said mouthportion; said inner surface including means for releasably connectingwith the distal end portion of the elongated member; said casing beingoperable to advance an elongated member through the tissue underlyingthe skin between different locations in the body in response to movementof a magnetic field across the skin extending between the locations. 11.The apparatus of claim 10 wherein said elongated member comprises anelectrical lead.
 12. The apparatus of claim 10 wherein said elongatedmember comprises a shunt catheter.
 13. The apparatus of claim 10 whereinsaid first end of said casing includes a semi-blunt tip.
 14. Theapparatus of claim 10 wherein second end of said casing includes aweighted flange.
 15. The apparatus of claim 10 wherein said means forreleasably connecting to the elongated member includes a portion of saidinner surface.
 16. The apparatus of claim 10 wherein said at least twobody portions of said casing are connected to each other by a hinge. 17.The apparatus of claim 10 further comprising a magnet for providing amagnetic field that is movable across the skin to cause correspondingsubcutaneous movement of said casing.
 18. An apparatus forsubcutaneously advancing an elongated member between different locationsin a mammalian body, said apparatus comprising: a casing made entirelyof a magnetic material, said casing having oppositely disposed first andsecond ends, said first end being closed and forming a tip portion ofsaid casing for tunneling through tissue underlying the skin, saidsecond end being open to form a mouth portion of said casing; saidcasing including annular inner and outer surfaces that extend betweensaid first and second ends and which define a side wall portion of saidcasing, said inner surface further defining a cavity within said casingfor receiving a distal end portion of the elongated member that projectsthrough said mouth portion; said inner surface including means forreleasably connecting with the distal end portion of the elongatedmember that include at least one support extending from said innersurface of said casing; said casing being operable to advance anelongated member through the tissue underlying the skin betweendifferent locations in the body in response to movement of a magneticfield across the skin extending between the locations.
 19. The apparatusof claim 18 wherein said at least one support includes an engagement padfor pressing against the elongated member with an interference fit. 20.The apparatus of claim 18 wherein said means for attaching to the deviceincludes a plurality of supports extending from said inner surface ofsaid casing.